Device and method for anchoring the terminal turns of the yarn to a cop of yarn

ABSTRACT

A device for anchoring the terminal turns of yarn (F) on a cop or reel (R) to prevent accidental unwinding is described. The device comprises at least one cylinder ( 19 ) whose cylindrical surface is equipped with a plurality of needles ( 21 ) projecting from said surface.

DESCRIPTION

[0001] The present invention relates to a device and a method for fastening or anchoring the outer terminal turns to a cap of yarn and consequently the tail of the yarn to prevent accidental unwinding during the following cop handling operations.

[0002] Yarns are subjected to a plurality of handling operations in the textile industry, passing through various types of machines which unwind and rewind the yarn to obtain the finished cop, which is then used as the starting material for the following processes, e.g. for dying or weaving or other. The tail of the yarn should not accidentally unwind from the cop during the cop handling operations because this could cause various types of difficulties during the production cycle and loss of material.

[0003] A known device for the at least partial anchoring of the tail of the yarn to the cop is described in Italian patent nr. 1,278,794 (application nr. F105A/240 dated Nov. 28, 1995). The known device employs a fixed brush which is pressed against the cop of yarn. The latter is kept turning and turns several times on its axis being brushed so that the bristles of the brush make the tail of the yarn adhere to the cop.

[0004] The results of the known device are appreciable with some types of yarn, but in some cases the simple brushing of the outer surface of the cop is not sufficient to efficiently anchor the tail of the yarn to the outer turns of the cop.

[0005] Object of the present invention is to realize a device and a method for providing efficient and reliable anchoring or adhesion of the tail of the yarn and the outermost turns of yarn on a cop, also if the yarn consists of a continuous synthetic filament, for example.

[0006] These and other objects and advantages, which will be clear to those skilled in the art from the text that follows, are obtained essentially by a device comprising at least one cylinder whose surface is equipped with a plurality of needles projecting from the surface. The needles can be oriented in the orthogonal direction to the axis of said cylinder or alternatively be slanted with respect to said axis.

[0007] The cylinder approaches and is pressed onto the cylindrical surface of the cop in the winding area of the last turns of yarn so that the needles penetrate in the pack of turns wound on the cop. The rotation of the cop drags the cylinder in rotation so that the needles move in and out of the pack of turns whereby developing a needle-punching effect on the surface of the cop. This makes the last turns mate and consequently anchors the tail of the yarn so that it cannot accidentally unwind from the cop.

[0008] The cylinder is advantageously idly supported on a respective rotation axis and rotation is provided by the cop which is turned on its axis. Nevertheless a driven cylinder may be used which turns the cop after coming into contact with its surface.

[0009] The device may be advantageously integrated in a spinning machine or any other textile machine which winds yarn on a reel or cop. In this way, the anchoring phase of the tail of the yarn on the cop is carried out at the end of the winding process. The device can however be configured as a stand-alone unit in which the cops are inserted to anchor the tail of the yarn. In this case, the device can comprise a rotating support for at least one cop and means for approaching the cylinder to the cop.

[0010] The needles can be suitably shaped to increase the turn retention effect, e.g. with a double tip or slanted grooves on the lateral surface (entangling needle or needle-punching needle). Advantageously, the needles project from the cylinder for a length comprised in the range from 1 to 10 mm and preferably from 2 to 4 mm. However, the needles may project by a different length, also in excess of 10 mm, from the surface of the cylinder.

[0011] The cylinder can be arranged to act on the cop always in the same axial position. This configuration can be adopted when the position along the axis of the cop where the last turns will be wound is known beforehand. When the position changes from cop to cop, the cylinder with needles can be positioned in a direction which is parallel to the axis of the cop and consequently parallel to its axis.

[0012] The invention also relates to a textile machine comprising means for winding yarn on a reel or cop, characterized in that it comprises at last one device as described above.

[0013] Additional features of the invention are recited in the annexed claims.

[0014] The invention will be better understood following the description and the accompanying drawing, which shows a non-limitative, practical example of the invention. In the drawing:

[0015]FIGS. 1 and 2 show a frontal view of the lower part of a textile machine in which the yarn is wound on cops in two subsequent process phases;

[0016]FIG. 3 shows a partial plan view according to III-III in FIGS. 1 and 2;

[0017]FIG. 4 shows a detail of the cylinder and needles;

[0018]FIGS. 5 and 6 show magnified details of two different forms of embodiment of a needle of the cylinder in FIG. 4.

[0019]FIGS. 1 and 2 very schematically show the application of the device according to the invention to a textile machine for the formation of reels or cops. In principle, the invention can be applied to any machine in which the yarn is wound on a cop, e.g. a spinning machine, a spooler or other. More in general, the device can also be a stand-alone unit in which the previously formed reels or cops are fitted on a mandrel (which turns them) and are subjected to the action of a cylinder with the needles for closing the tail of the yarn.

[0020] In the embodiment shown in FIGS. 1 and 2, the yarn F is fed towards the lower part of the machine where it is wound on the tubes T fitted on a supporting mandrel M. The supporting mandrel M is supported by an arm 1 turning on an axis A-A. As appears in FIG. 3, three tubes T are actually fitted on the mandrel M where three corresponding reels R are formed in parallel by feeding three threads F. Two mandrels M are fitted on the arm 1 and work alternatively as explained below.

[0021] Yarn F is turned around a roller 3 before being wound on the reel R. A traversing device or traverse, known per se, is arranged inside a case 5 and distributes the yarn on the entire axial development of each reel R.

[0022] As appears in FIGS. 1 and 2, the arm 1 turns gradually counterclockwise progressively as the diameter of the reels R fitted on the mandrel M increase to reach the final dimension.

[0023] The machine is equipped with a double pivoting arm 9 (FIG. 3), pivoting on an axis B-B which is parallel to the axis A-A of the rotating arm 1. The movement of the pivoting arm 9 is controlled by a cylinder-piston actuator 11, whose cylinder is fastened at 13 to a shelf 15 carried by the machine.

[0024] A crosspiece 15—onto which three pairs of brackets 17 are integrally fastened—is carried by the double arm 9. Each of the pairs of brackets 17 supports a shaft onto which a respective cylinder 19 is idly mounted. The cylinder 19 is shown in detail in FIG. 4.

[0025] The surface of the cylinder 19 is equipped with a plurality of needles 21 projecting radially with respect to the cylindrical surface. The distribution of the needles 21 is relatively sparse: the needles 21 may be distributed along generatrixes reciprocally distanced by approximately 10-60° on a cylinder 19 with an axial length of approximately 5 cm and from two to five needles can be distributed on each generatrix, although this distribution is not mandatory.

[0026]FIGS. 5 and 6 show two different possible configurations for the needles 21. These two configurations can be used either alternatively or in combination on the same cylinder. In the embodiment shown in FIG. 5, the needle 21 is equipped with a double tip 21A, in the form of a fork. In the configuration shown in FIG. 6, the needle is a so-called entangling needle, i.e. a needle equipped with grooves 21B suitably directed along the development of the needle, for the purposes better described below. The needle of this second configuration is essentially a mechanical entangling needle although, of a shorter length.

[0027] During the final phase of reel or cop winding process (FIG. 2), the double pivoting arm 9 is taken to the position shown in FIG. 2, where the cylinders 19 are pressed against the outer surface of the developing reel R before the process is completed. The position of the cylinders 19 corresponds to the area in which the yarn is fed by the traverse during this phase, so that the needles 21 of the cylinder 19 penetrate between the turns of yarn in the area in which these are forming. The contact between the cylinder 19 and the outer surface of the reel (cylindrical or conical) drags the cylinder 19 in rotation which therefore rolls on the outer surface of the reel in the area where the final turns are developing. The penetration of the needles in the pack of turns forming the body of the reel or cop makes the last turns of yarn “mate” so that the last turns can only be unwound by voluntarily pulling the free end of the yarn and not come loose accidentally when the yarn is cut to form the tail after the winding process.

[0028] The conformation of the needles shown in FIGS. 5 and 6 facilitates the “mating” operation because the double tip 21A of the needle in FIG.5 or the grooves 21B of the entangling needle 21 in FIG. 6 at least partially drag the yarn inwards when the needle penetrates in the body of the cop and the yarn is not pulled out when the needle is successively extracted. Essentially, the needles 21 of the cylinder 19 have an effect which is similar to that of a mechanical entangling machine. Needles of other shapes may be employed.

[0029] It is understood that the drawing just shows a practical example of the invention, since numerous changes can be implemented to its construction and embodiments without departing from the scope of the present invention. 

What I claim is:
 1. A device for stopping the last turns of yarn on a cop of yarn to prevent accidental unwinding, which includes at least a cylinder which is equipped, on its cylindrical surface, with a plurality of needles projecting from said surface.
 2. Device according to claim 1, wherein said cylinder is idly supported on a respective rotation axis.
 3. Device according to claim 1, wherein said needles have a double tip.
 4. Device according to claim 2, wherein said needles have a double tip.
 5. Device according to claim 1, wherein said needles are entangling needles.
 6. Device according to claim 2, wherein said needles are entangling needles
 7. Device according to one or more of the preceding claims, wherein the needles project from the cylinder by a length comprised in the range from 1 to 10 mm, and preferably from 2 to 4 mm.
 8. Device according to one or more of claims 1 to 6, wherein said cylinder is equipped with a translation movement which is parallel to its axis.
 9. Device according to one or more of claims 1 to 6, including a rotating support for at least one cop and means for approaching the cylinder to the cop.
 10. Device according to one or more of claims 1 to 6, wherein said needles project from the surface of the cylinder in a direction which is orthogonal to the axis of the cylinder.
 11. A textile machine comprising means for winding a yarn on a reel or cop, including at least a device according to one or more of the claims 1 to
 6. 12. Machine according to claim 11, including a pivoting arm which idly support said at least one cylinder, the pivoting arm being capable of alternatively assuming a non-working position, in which the cylinder is held at a distance from said reel or cop, and a working position in which the cylinder is moved against a cop during winding completion.
 13. Machine according to claim 12, wherein the pressure with which the cylinder is pressed against the cop is variable.
 14. A method for anchoring the end turns of a cop of yarn and prevent accidental unwinding thereof, wherein a cylinder equipped with needles is moved against the cylindrical surface of the cop in the winding area of the last turns of yarn, and the cop is turned whereby turning the cylinder, the needles penetrating in the turns of yarn causing reciprocal mating of the turns.
 15. Method according to claim 14, wherein the turns are anchored to the cop at the end of the yarn winding phase on the cop in a textile machine for the development of cops of yarn. 